108 lines
2.4 KiB
PHP
108 lines
2.4 KiB
PHP
<?php
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declare(strict_types=1);
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namespace Phpml\Classification\DecisionTree;
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class DecisionTreeLeaf
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{
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const OPERATOR_EQ = '=';
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/**
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* @var string
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*/
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public $value;
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/**
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* @var int
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*/
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public $columnIndex;
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/**
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* @var DecisionTreeLeaf
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*/
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public $leftLeaf = null;
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/**
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* @var DecisionTreeLeaf
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*/
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public $rightLeaf= null;
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/**
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* @var array
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*/
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public $records = [];
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/**
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* Class value represented by the leaf, this value is non-empty
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* only for terminal leaves
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*
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* @var string
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*/
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public $classValue = '';
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/**
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* @var bool
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*/
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public $isTerminal = false;
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/**
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* @var float
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*/
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public $giniIndex = 0;
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/**
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* @var int
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*/
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public $level = 0;
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/**
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* @param array $record
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* @return bool
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*/
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public function evaluate($record)
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{
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$recordField = $record[$this->columnIndex];
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if (preg_match("/^([<>=]{1,2})\s*(.*)/", $this->value, $matches)) {
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$op = $matches[1];
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$value= floatval($matches[2]);
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$recordField = strval($recordField);
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eval("\$result = $recordField $op $value;");
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return $result;
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}
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return $recordField == $this->value;
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}
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public function __toString()
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{
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if ($this->isTerminal) {
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$value = "<b>$this->classValue</b>";
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} else {
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$value = $this->value;
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$col = "col_$this->columnIndex";
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if (! preg_match("/^[<>=]{1,2}/", $value)) {
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$value = "=$value";
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}
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$value = "<b>$col $value</b><br>Gini: ". number_format($this->giniIndex, 2);
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}
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$str = "<table ><tr><td colspan=3 align=center style='border:1px solid;'>
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$value</td></tr>";
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if ($this->leftLeaf || $this->rightLeaf) {
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$str .='<tr>';
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if ($this->leftLeaf) {
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$str .="<td valign=top><b>| Yes</b><br>$this->leftLeaf</td>";
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} else {
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$str .='<td></td>';
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}
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$str .='<td> </td>';
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if ($this->rightLeaf) {
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$str .="<td valign=top align=right><b>No |</b><br>$this->rightLeaf</td>";
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} else {
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$str .='<td></td>';
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}
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$str .= '</tr>';
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}
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$str .= '</table>';
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return $str;
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}
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}
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